SMSL SU-1 Stereo DAC Review

[2chLover]

have u try to use die USB input for sending audio data?

 

[Monster]

have u try to use die USB input for sending audio data?

I have.

I actually couldn't even get the Win 10 computer to recognise the the SU-1 was connected. That's even with the SMSL XMOS driver installed. But really I only want to use it with either coaxial or optical input from my Wiim Pro.

 

[2chLover]

That's clear. It's just to clarify what might be wrong. I have no idea what it could be...

 

[Monster]

That's clear. It's just to clarify what might be wrong. I have no idea what it could be...

Me neither.

 

[Toku]

Me neither.

What equipment is connected to the OPT and COAX inputs?
Is the input audio signal a pure 2-channel stereo signal?

Audio DACs such as the SU-1 only function properly with pure 2-channel stereo signals. They cannot reproduce signals that include sound effects such as Dolby.

 

[tccalvin]

Me neither.

I might be completely off base here, but check if you're feeding enough power to the thing. It consumes around 5W (per manufacturer spec) so USB 2.0 won't cut it (max 2.5W) and likely neither will a power supply that can't do at least 5V*1A.

EDIT: Also, don't use fast charging since these products often don't support Power Delivery.

 

[staticV3]

I might be completely off base here, but check if you're feeding enough power to the thing. It consumes around 5W (per manufacturer spec) so USB 2.0 won't cut it (max 2.5W) and likely neither will a power supply that can't do at least 5V*1A.

The SU-1 consumes around 1.3W during playback:

S

Post in thread 'SMSL SU-1 Stereo DAC Review'

Feb 2, 2024

I can't see power consumption on boot, but as soon as the power meter starts measuring it hovers around 1,3W, doesn't matter if it is playing music or not.

• strumf666

• 

Insufficient power is unlikely.

 

[2chLover]

Correct. That is also my experience. about 1 watt

 

[Monster]

What equipment is connected to the OPT and COAX inputs?
Is the input audio signal a pure 2-channel stereo signal?

Audio DACs such as the SU-1 only function properly with pure 2-channel stereo signals. They cannot reproduce signals that include sound effects such as Dolby.

I tried both optical and coaxial connections from two Wiim Pros. Nothing out from the SU-1 with either, although the input signal was detected.

 

[Toku]

I tried both optical and coaxial connections from two Wiim Pros. Nothing out from the SU-1 with either, although the input signal was detected.

The SU-1 detects all signals connected to the OPT and COAX inputs and displays the connection status, but can only output pure stereo 2ch input audio signals.

 

[Monster]

The SU-1 detects all signals connected to the OPT and COAX inputs and displays the connection status, but can only output pure stereo 2ch input audio signals.

Indeed. I tried connecting the output to two different stereo amplifiers during testing. A Douk Audio A5 and a Cambridge Audio AXA35. No sound out of either amplifier with the SU-1 installed.

When testing with the AXA35 system, which is my main system, I put the SU-1 in the place of the my SMSL C100, with no success. No sound out of the speakers. Put the C100 back in place and the system all works as it should.

 

[Toku]

Indeed. I tried connecting the output to two different stereo amplifiers during testing. A Douk Audio A5 and a Cambridge Audio AXA35. No sound out of either amplifier with the SU-1 installed.

When testing with the AXA35 system, which is my main system, I put the SU-1 in the place of the my SMSL C100, with no success. No sound out of the speakers. Put the C100 back in place and the system all works as it should.

If it works fine after replacing it with the C100, then the SU-1 is faulty.
But I would have liked to have known that information first.

 

[michalzienia]

Hi. Can I connect this DAC directly to the power amplifier IOTAVX PA3 and control the volume through Windows?

 

[tccalvin]

Hi. Can I connect this DAC directly to the power amplifier IOTAVX PA3 and control the volume through Windows?

yep

 

[Monster]

Thanks to @2chLover , @SoySalsaPicante and @Toku for your input into this problem. I think the conclusion must be the SU-1 is indeed broken and not reparable.

This morning I have had delivery of a Fosi Audio Q6, again bought off eBay at a knock down price. This looks nearly new and, even better, it actually works and sounds good. The only downside is that it is more than twice the size of the SU-1 but if it's reliable I will take that in preference.

 

[2chLover]

Hello. As I wrote before, the SU-1 replaces the internal DAC in my Philips player CD-824 from 1991 and improved so the analog signal significantly. To prevent interference and noise from a cell phone charger from entering the SU-1's signal path, I designed an analog power supply and built it into the CD player.
The CDP has enough space for another circuit board (pic1), and the 5V voltage is routed out via two USB-C ports (pic3).
The DAC is now powered via a short cable. (pic4)
It's not worth discussing the impact and usefulness of the modification. I believe that switching power supplies have no place in high-quality audio applications. And yes, I know that the SU-1 has a non-analog circuit internally to power the op-amps in the output stage. In that sense, my modification is only half the battle. Can I hear an improvement? I don't think so. But I feel better now!

 

[Silvestrus]

What is the general consensus on the preferred input from the WiiM Pro Plus — optical or coax?

 

[SoySalsaPicante]

What is the general consensus on the preferred input from the WiiM Pro Plus — optical or coax?

Either one will be sufficiently transparent; optical will better avoid any potential grounding issues and any difference in jitter versus coax is minimal enough to be impossible to pick out in blind A/B testing against the other.

 

[Roland68]

Hello. As I wrote before, the SU-1 replaces the internal DAC in my Philips player CD-824 from 1991 and improved so the analog signal significantly. To prevent interference and noise from a cell phone charger from entering the SU-1's signal path, I designed an analog power supply and built it into the CD player.
The CDP has enough space for another circuit board (pic1), and the 5V voltage is routed out via two USB-C ports (pic3).
The DAC is now powered via a short cable. (pic4)
It's not worth discussing the impact and usefulness of the modification. I believe that switching power supplies have no place in high-quality audio applications. And yes, I know that the SU-1 has a non-analog circuit internally to power the op-amps in the output stage. In that sense, my modification is only half the battle. Can I hear an improvement? I don't think so. But I feel better now!

You're wrong in your opinion, or rather, you've long since been out of date.
I used to think that too, and it was justified. I'm now even replacing linear power supplies with filtered SMPS.
The wall wart filter from the diyaudio forum gets a cleaner output voltage from a simple switching power supply than your linear power supply delivers. Much smaller, less effort, more gain.

 

[Silvestrus]

Blinking light issue solved.